Abstract:
Die Erfindung betrifft ein Verfahren zum Starten einer Brennstoffzelle sowie ein zum Ausführen des Verfahrens eingerichtetes Brennstoffzellensystem. Die Brennstoffzelle umfasst elektrisch leitende Bipolarplatten, zwischen denen jeweils eine Kathode, umfassend einen fluidführenden Kathodenraum, eine Membran und eine Anode, umfassend einen fluidführenden Anodenraum, angeordnet sind. Es ist vorgesehen, dass das Verfahren die folgenden Schritt ein der angegebenen Reihenfolge umfasst: –Spülen des Anodenraums mit einem Fluid zum Austreiben von Brennstoff, –Aufprägen einer Elektrizität auf eine Einheit aus Kathode (2k) / Membran (1) / Anode (2a), mittels Anlegen eines Stroms und/oder einer Spannung,wobei der Anodenraum mit dem Fluid beaufschlagt wird oder bleibt, –Abschalten der Elektrizität, und –Einbringen eines Brennstoffs in den Anodenraum.
Abstract:
Die Erfindung betrifft ein Brennstoffzellensystem (2) mit wenigstens einem Brennstoffzellenstapel (3), welcher in einem Gehäuse (7) angeordnet ist, wobei das Gehäuse (7) wenigstens eine Belüftungsverbindung (8, 9) zur Umgebung oder einem anderen Volumen aufweist. Die Erfindung ist dadurch gekennzeichnet, dass die Belüftungsverbindung (8, 9) eine Ventileinrichtung (18, 19).
Abstract:
The present invention is directed to a redox flow battery comprising at least one electrochemical cell in fluid communication with a balancing cell, said balancing cell comprising: a first and second half-cell chamber, wherein the first half-cell chamber comprises a first electrode in contact with a first aqueous electrolyte of the redox flow battery; and wherein the second half-cell chamber comprises a second electrode in contact with a second aqueous electrolyte, said second electrode comprising a catalyst for the generation of O 2 .
Abstract:
A PEM fuel system includes a fuel cell stack comprising one or more PEM fuel cells and fan configured to provide process air to supply oxidizer to and cool the fuel cell stack. The system has an air duct coupled to the fan and the fuel cell stack, and an electrical service load coupled to the fuel cell stack for receiving electrical power generated from reactions within the fuel cell stack. The system further includes as auxiliary electrical load coupled to the fuel cell stack and located within the air duct to reduce potentials across the fuel cell stack. The air duct is configured to direct the flow of air to the fuel cell stack and auxiliary electrical load to provide cooling air to the fuel cell stack and auxiliary electrical load.
Abstract:
The invention relates to a method for protecting against corrosion in an assembly of electrochemical cells (C1, C2, C3) included in a fuel cell during the extinction phase of the fuel cell, including the steps of: measuring the voltage across the terminals of each of the cells to be protected; when the measured voltage of a cell is higher than a protection threshold, discharging (50) said cell into an electric load (R1, R2, R3); and, when the measured voltage of a cell is lower than said protection threshold, uncoupling said cell from the electric load.
Abstract:
Verfahren zum Betrieb einer Brennstoffzelle, insbesondere zum Abschalten einer Brennstoffzelle. Zum Abschalten der Brennstoffzelle wird die Zufuhr des Gasgemisches, welches Sauerstoff und Stickstoff enthält, unterbrochen wird, wobei der an der Kathode vorliegende Sauerstoff durch Umsetzung mit den vorhandenen Protonen abreagiert und der Restsauerstoff gehalt an der Kathodenseite der Brennstoffzelle so abgesenkt wird. Durch das erfindungsgemäße Verfahren kann eine Brennstoffzelle besser gelagert werden, wobei an den beiden Elektroden ein definiert niedriges chemisches Potential anliegt.
Abstract:
Disclosed is a segmented modular solid oxide fuel cell device having a plurality of independently controllable electrical power producing segments disposed within a common thermal environment. Also disclosed are methods for selectively operating one or more segments of the disclosed segmented modular solid oxide fuel cell device. Also disclosed are methods for performing a maintenance process on one or more segments of a segmented modular fuel cell device during fuel cell operation.
Abstract:
A decontamination procedure for a fuel cell power plant (10) includes operating the plant to produce electrical power for an operating period, and then terminating operation of the plant (10) for a decontamination period, and then, whenever optimal electrical production of a plant fuel cell (12) is reduced by at least 5 % by contaminants adsorbed by a fuel cell electrodes (24, 42), decontaminating the fuel cell (12) of the plant (10) during the decontamination period by oxidizing contaminants adsorbed by electrodes (24, 42) of the fuel cell. Oxidizing the contaminants may be accomplished by various steps including exposing the electrodes (24, 42) to flowing oxygen; to heated flowing oxygen; to a sequence of start-stop cycles; and, to varying controlled potentials.
Abstract:
A process for the activation of a membrane electrode assembly, such as a direct methanol fuel cell membrane electrode assembly, with a hydrocarbon fuel, e.g., an alkanol fuel such as methanol, and an oxidant is described. The process comprises repeatedly applying an increasing or decreasing potential in each of a plurality of cycles over a voltage range of at least 0.1 volts, e.g., at least 0.2 volts or at least 0.3 volts, until the membrane electrode assembly is substantially activated. The cycles optionally are organized in cycle sets with rest periods therebetween. The temperature at which the cycles are run optionally is increased or decreased in a respective cycle set.
Abstract:
A fuel cell power plant (20) includes a variable resistive device (30). In one example, the variable resistive device (30) is operationally associated directly with a cell stack assembly (22). The controller (32) selectively varies an electrical resistance of the variable resistive device (30) responsive to an operating condition of the power plant (20). By using a variable resistive device, a variety of control functions are possible to address various operating conditions of the power plant (20) or the cell stack assembly (22).